| Abstract: | Thalamic neuronal projections to the parietal association cortex were investigated in cats applying techniques of retrograde axonal transport of two fluorescent dyes (primuline and fast blue). The dorsal thalamic pulvinar (PL) as well as the dorsal and caudal lateral posterior nucleus (LP) were found to project mainly to the central suprasylvian gyrus (CSSG), while the ventral PL and the ventrorostral LP send out projections to rostral sites of the same gyrus (RSSG). Neurons with dual labeling were found in the PL, LP, suprageniculate, anteroventral, and ventrolateral thalamic nuclei following a single injection of two different markers into the RSSG and CSSG, as well as the centrolateral, paracentral, and centromedial nuclei. Topical organization of sources of cortical projections within the PL-LP complex can apparently provide a high level of discrimination of visual signals by individual cortical units. At the same time, the RSSG and CSSG appear to function in harmony to a considerable extent during integration of information of differing cortical origin; this could point to a lack of differentiation on the part of the RSSG and CSSG, corresponding to feline cortical areas 5 and 7 approximately.Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR, Moscow. A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 23, No. 2, pp. 135–142, March–April, 1991. |
